eom: list hicolor_icon_theme after gtk

There is a bug on the glib hooker that prevents running its pre fixup
phase if it is listed before hicolor_icon_theme in the dependencies of a
derivation.

pkgs/desktops/mate/eom/default.nix

···
     pkgconfig
     intltool
     itstool
-    hicolor_icon_theme
     wrapGAppsHook
   ];
 
···
     gnome3.gtk
     gnome3.libpeas
     mate.mate-desktop
+    hicolor_icon_theme
   ];
 
   meta = {